feat: first commit

backend/internal/domain/errors.go

@@ -0,0 +1,18 @@
+package domain
+
+import "errors"
+
+// Sentinel errors crossing the port boundary. Adapters translate infra errors
+// into these; HTTP layer maps these to status codes.
+var (
+	ErrNotFound     = errors.New("not found")
+	ErrCodeTaken    = errors.New("code already taken")
+	ErrReserved     = errors.New("code is reserved")
+	ErrInvalidURL   = errors.New("invalid destination url")
+	ErrInvalidAlias = errors.New("invalid custom alias")
+	ErrInvalidPin   = errors.New("pin must be exactly 6 digits")
+	ErrUnauthorized = errors.New("authentication required")
+	ErrForbidden    = errors.New("not allowed")
+	ErrPinRequired  = errors.New("pin required")
+	ErrPinInvalid   = errors.New("incorrect pin")
+)

backend/internal/domain/link.go

@@ -0,0 +1,49 @@
+package domain
+
+import "time"
+
+// Mode is how a short code was produced.
+type Mode string
+
+const (
+	ModeRandom    Mode = "random"
+	ModeMemorable Mode = "memorable"
+	ModeCustom    Mode = "custom"
+)
+
+// DayCount is a single day's click total.
+type DayCount struct {
+	Date  string `json:"date"`
+	Count int64  `json:"count"`
+}
+
+// Link is the aggregate root: a short code pointing at a destination.
+type Link struct {
+	ID          string
+	Code        string
+	LongURL     string
+	Mode        Mode
+	HasPin      bool
+	PinHash     string // bcrypt hash; never serialized out of the system
+	OwnerID     string // empty for anonymous links
+	CreatedAt   time.Time
+	TotalClicks int64
+	Last7Days   []DayCount
+}
+
+// OwnerStats are the dashboard aggregate tiles, computed in the DB so the
+// client never has to fetch every link to total them up.
+type OwnerStats struct {
+	TotalLinks  int   `json:"totalLinks"`
+	TotalClicks int64 `json:"totalClicks"`
+	WeekClicks  int64 `json:"weekClicks"`
+}
+
+// User is an authenticated account, keyed by (provider, subject).
+type User struct {
+	ID       string
+	Email    string
+	Name     string
+	Provider string
+	Subject  string
+}